An
image of the COVID-19 test chip made by aerosol jet nanoparticle 3D printing. Credit:
Advanced Manufacturing and Materials Lab, Carnegie Mellon University.
Researchers
at Carnegie Mellon University report findings on an advanced nanomaterial-based
biosensing platform that detects, within seconds, antibodies specific to
SARS-CoV-2, the virus responsible for the COVID-19 pandemic. In addition to
testing, the platform will help to quantify patient immunological response to
the new vaccines with precision.
The
results were published this week in the journal Advanced Materials. Carnegie
Mellon's collaborators included the University of Pittsburgh (Pitt) and the
UPMC.
The
testing platform identifies the presence of two of the virus' antibodies, spike
S1 protein and receptor binding domain (RBD), in a very small drop of blood
(about 5 microliters). Antibody concentrations can be extremely low and still
detected below one picomolar (0.15 nanograms per milliliter). This detection
happens through an electrochemical reaction within a handheld microfluidic
device which sends results almost immediately to a simple interface on a smart
phone.
"We
utilized the latest advances in materials and manufacturing such as
nanoparticle 3-D printing to create a device that rapidly detects COVID-19
antibodies," said Rahul Panat, an associate professor of mechanical
engineering at Carnegie Mellon who uses specialized additive manufacturing techniques
for research ranging from brain-computer interfaces to biomonitoring devices.
An
additive manufacturing technology called aerosol jet 3-D printing is
responsible for the efficiency and accuracy of the testing platform. Tiny,
inexpensive gold micropillar electrodes are printed at nanoscale using aerosol
droplets that are thermally sintered together. This causes a rough, irregular
surface that provides increased surface area of the micropillars and an
enhanced electrochemical reaction, where antibodies can latch on to antigens
coated on the electrode. The specific geometry allows the micropillars to load
more proteins for detection, resulting in very accurate, quick results.
The test
has a very low error rate because the binding reaction between the antibody and
antigen used in the device is highly selective. The researchers were able to
exploit this natural design to their advantage.
The
results come at an urgent time during the COVID-19 pandemic. "Because our
technique can quantify the immune response to vaccination, it is very relevant
in the current environment," Panat said.
Panat
collaborated with Shou-Jiang Gao, leader of the cancer virology program at
UPMC's Hillman Cancer Center and professor of microbiology and molecular
genetics at Pitt. Azahar Ali, a researcher in Panat's Advanced Manufacturing
and Materials Lab, was the lead author of the study.
Rapid
diagnosis for the treatment and prevention of communicable diseases is a public
health issue that goes beyond the current COVID-19 pandemic. Because the
proposed sensing platform is generic, it can be used for the rapid detection of
biomarkers for other infectious agents such as Ebola, HIV, and Zika. Such a
quick and effective test could be a game-changer for controlling the spread of
diseases.